Los Reyes Project

Sinaloa, Mexico


Located 43 kilometres south east of the mining centre of Cosala, Sinaloa, Los Reyes has an extensive mining history that stretches back into the 1700s. Recent development work has focused on conventional milling and carbon in leach extraction of gold and silver. The Company envisions a simple heap leach operation that potentially has significantly lower capital costs and shortened time line to production. Los Reyes has significant resource upside with open extensions to known resources as well as eight additional discrete exploration targets.

“Los Reyes is an exceptional opportunity for exploration and potential development poised to fast-track through a preliminary economic assessment (PEA) with a construction decision based on low capital expenditure and reduced technical risks. The Company will work to complete the feasability study while continuing to drill in order to expand existing data as well as identify promising new targets.”                         —Company CEO, Andrew Bowering

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Maps & Technical Data

NI 43-101 Technical Report (April 2020).


Gold and silver were discovered at Los Reyes by the Spanish in the late 1700s and mining occurred in the area for over 150 years up until the 1950s. The Guadalupe de los Reyes underground mine opened in the late 1800s and to date is the most significant source of gold production in the district. It is estimated to have produced 500-600,000 oz of gold and 40M oz of silver at reported grades of +10 g/t Au and +500 g/t Ag.

From the 1950s through the 1980s there was limited activity in the Los Reyes area other than mostly exploration reconnaissance studies. Modern drilling began at the Los Reyes area in the 1990s and was targeted at defining shallow and lower-grade gold-silver mineralization in areas surrounding the Los Reyes underground operations. Since that time, over 40,000 meters of RC and core drilling have been completed within the current project boundaries resulting in extensive area-wide resource data.

Why Los Reyes?

Los Reyes hosts well-advanced:
Gold resources of:
380,000 oz
155,000 oz
Silver resources of:
6,315,300 oz
3,639,000 oz
Established and operating in Sinaloa, Mexico with additional early stage gold/silver opportunities

Conceptual Path to Production

Los Reyes was on-track to become a heap leach mine in 1998...
When gold prices dropped the project was mothballed.

Previous work includes

  • 493 Holes with over 46,000 meters drilled
  • Location and layout of open pits on five deposits has been established
  • Metallurgical tests show heap leach recovery as a viable option
  • A leach pad sited and designed to prefeasibility standards

Past efforts propel Prime Mining’s fast track approach to production

Simplified, time saving, low cost plan to achieve operations

  • Low capital open pit mine with heap leach processing
  • Onsite gold loading on carbon, no ADR or Merrill-Crowe Plant
  • Contract mining & contract crushing
  • Contract, offsite carbon stripping, refining and gold production

Notes on Historic Resources

Los Reyes Conceptual Site Plan

Amenable to simple open pit heap leach mining, and plans are to engineer, permit and construct in 2 years.
Capital structure values company at $20 per ounce gold (peer average $55).
Tens of millions already spent in exploration & engineering studies, 5 open pit deposits delineated.
Holds great upside potential for both resource expansion, along strike, down dip, at depth, and in new areas.
Experienced management team very familiar with the region and open pit heap leach operations; local team already in place.

Our Value Proposition

Near term low cost production on current resources
380,000 OZ GOLD
indicated (1.73 g/t)
155,000 OZ
inferred (1.49 g/t)
And significant silver credits, amenable to heap leach.
500,000 tonnes
At 3.2 g/t Au
With no initial pre-strip required for potential 6 month pay back of start-up capital.
0.5 g/t
Currently modelled at 0.5 g/t cutoff potential to rework models at 0.25 g/t adding ounces
76% Au and 24% Ag
Proven heap leach recoveries with upside from optimization. (*PFS by Pincock, Allen & Holt, 1998)
1.73 g/t
1.73 g/t gold average on indicated resource grade

Exceptional exploration upside with current and new targets

  • Current resources open on strike and to varying depths.
  • 8 to 10 new high grade underexplored surface discoveries for drill testing.
  • Untested new claim blocks added to project yet to have any exploration

Consolidation opportunity and partnership

  • Partnership with Minera Alamos paves the way to capitalize on their early mover success
  • Potential consolidation of assets and operations into mid-tier producer at a later date

Property Details


  • Ownership of 6,300 hectares in mining friendly Sinaloa State;
  • Close proximity to infrastructure including: water, power, roads and population.

Recent History

  • Current owner united all claims blocks and surrounding lands over last 10 years.


  • 8 additional new high-grade surface targets
  • Existing deposits open to expansion
  • Depth never explored

Mine Planning Stage

  • Current resource is ready to take to PEA with detailed engineering on simple 3/8″ to 1/2″ crush leach operation
Epithermal Veins in a District Scale Project
Mining Friendly District

Claim Consolidation Added

  • Open “on strike” potential
  • Untested new zones including Las Primas, San Miguel, Chiripa, and Mariposa
  • Untested surface showings.

Mineral Resource

Indicated & Inferred Resources at a Cut-off Grade of 0.50  g/t Au
Indicated Tonnes Kt Au oz Au g/T Ag oz Ag g/T
El Zapote 3,980 206,000 1.61 2,114,135 16.52
Noche Buena 937 39,700 1.32 497,400 16.52
San Miguel – Chiripa 459 47,100 3.19 1,141,800 77.37
Guadalupe 1,520 86,300 1.76 2,601,800 52.51
Total Indicated 6,843 380,100 1.73 6,315,300 28.71
Inferred  Tonnes Kt  Au oz Au g/T  Ag oz Ag g/T
El Zapote 1,127 44,800 1.25 428,600 11.82
Noche Buena 480 17,400 1.13 275,000 17.8
San Miguel – Chiripa 583 41,500 2.21 1,215,000 64.75
Guadalupe 1,054 51,600 1.52 1,720,500 50.75
Total Inferred 3,200 155,200 1.49 3,639,000 34.87
  1. The resource model for Los Reyes was prepared by Tetra Tech, Inc. of Golden, Colorado for Minera Alamos dated April 16, 2018. In their updated report for Prime Mining, it was determined to identify the resource as historic (per NI 43-101 compliance), until the Company can recalculate & restate the resource.
  2. To the knowledge, information and belief of Minera Alamos, there is no new material or scientific or technical information that would make the disclosure of the mineral resources in the Report inaccurate or misleasding.
  3. Mineral resources were calculated based on a cut-off grade of 0.5 g/t Au.
  4. No measured resources or mineral reserves of any category are identified. Mineral resources that are not mineral reserves do not have a demonstrated economic viability.
  5. It is Prime Mining’s intention to deliver a new, updated and restated resource model for Los Reyes in late 2019.

4 Delineated Deposits

  • Guadalupe, East/West
  • El Zapote
  • San Miguel / Chirpa
  • Noche Buena

Sample Historic Drill Results

  • ZA58 - 28m at 4.09 g/t Au, 24 g/t Ag
  • ZA85 - 57.9m at 2.49 g/t Au, 16 g/t Ag
  • GS62 - 33.5m at 3.9 g/t Au, 173 g/t Ag
  • SM3 - 12.19m at 5.74 g/t Au, 53 g/t Ag

Exploration Potential


  • Over 17.5 kilometres of mineralized strike length;
  • 10 kilometres of untested strike;
  • Multiple high grade surface grabs with no follow up;
  • 15.1, 14.8 and 9.5 g/t gold at surface;
  • Numerous surface showings untested.

Significant Undervaluation to Peers

$20 USD
Prime Mining
$55 Resource
$38 Engineered
Haywood/Bloomberg Global Average EV/oz Au

1. Enterprise Value (“EV”)/Gold Resource Ounce is a non-IFRS performance measures. Enterprise value is calculated as of April 11, 2019. Data sourced from Haywood Securities and Bloomberg.

Timeline & Performance Milestones

1-3 months
  • Exploration & drill permitting, establish logistics & ground operations
  • Begin surface exploration, trenching, metallurgical sampling & environmental review
  • Begin remodeling resource data set
6-12 months
  • Geotechnical and condemnation drilling, exploration drilling
  • Updated resource model and PEA Study
  • Agreements and permits for construction decision
30 months

Gold recovery & anticipated profits

3-6 months
  • Metallurgical studies, exploration and geotechnical drilling
  • Deliver new resource model, continue engineering and metallurgical work for PEA study
12-24 months
  • Award contracts and start construction of gold recovery plant and heap leach infrastructure
  • Award contract for contract mining, mobilize fleet and start pit development

Notes on Historic Resources

1. The Company recently purchased the Los Reyes asset and has deemed the resources outlined on this page as historic until the completion an independent assessment and resource calculation.

2. Mineral resources that are not mineral reserves do not have demonstrated economic viability.

The Company does not treat historical estimates as current and has not completed sufficient work to classify historical estimates as current mineral resources. The Company does believe the previous work is reliable and the information, which was made publicly available at the time, may be of assistance to readers. As part of its due diligence process, and as required by the policies of the Exchange, the Company has commissioned Tetra Tech, Inc. to prepare a revised Los Reyes geological report which is expected to contain a new resource estimate. Once completed, a copy of the report will be available for review via the Company’s profile on SEDAR (